Precisely Tailoring Upconversion Dynamics Via Energy Migration in Core-Shell Nanostructures
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UvA-DARE (Digital Academic Repository) Precisely Tailoring Upconversion Dynamics via Energy Migration in Core-Shell Nanostructures Zuo, J.; Sun, D.; Tu, L.; Wu, Y.; Cao, Y.; Xue, B.; Zhang, Y.; Chang, Y.; Liu, X.; Kong, X.; Buma, W.J.; Meijer, E.J.; Zhang, H. DOI 10.1002/anie.201711606 10.1002/ange.201711606 Publication date 2018 Document Version Final published version Published in Angewandte Chemie, International Edition License CC BY-NC Link to publication Citation for published version (APA): Zuo, J., Sun, D., Tu, L., Wu, Y., Cao, Y., Xue, B., Zhang, Y., Chang, Y., Liu, X., Kong, X., Buma, W. J., Meijer, E. J., & Zhang, H. (2018). Precisely Tailoring Upconversion Dynamics via Energy Migration in Core-Shell Nanostructures. Angewandte Chemie, International Edition, 57(12), 3054-3058. https://doi.org/10.1002/anie.201711606, https://doi.org/10.1002/ange.201711606 General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You willUvA-DARE be contacted is a service as provided soon as by possible.the library of the University of Amsterdam (https://dare.uva.nl) Download date:26 Sep 2021 Angewandte Communications Chemie International Edition:DOI:10.1002/anie.201711606 Upconversion German Edition:DOI:10.1002/ange.201711606 Precisely Tailoring Upconversion Dynamicsvia Energy Migration in Core–Shell Nanostructures Jing Zuo+,Dapeng Sun+,Langping Tu+,Yanni Wu,Yinghui Cao,Bin Xue,Youlin Zhang, Yulei Chang,Xiaomin Liu, Xianggui Kong,* Wybren JanBuma, Evert JanMeijer,* and Hong Zhang* Abstract: Upconversion emission dynamics have long been biology,[2] anti-counterfeiting,[3] and solar cells.[4] Recent believed to be determined by the activator and its interaction advances in upconversion emission applications rely more with neighboring sensitizers.Herein this assumption is,how- and more on precisely engineering the material structure on ever,shown to be invalid for nanostructures.Wedemonstrate nanometer scale,inwhich energy migration behavior plays that excitation energy migration greatly affects upconversion akey role.Sofar, most of the related investigations have emission dynamics.“Dopant ions spatial separation” nano- focused on steady-state effects of energy migration.[5] That is, structures are designed as model systems and the intimate link excited states could randomly “walk”, thus making the long- between the random nature of energy migration and upcon- range energy transport (more than several nanometers) version emission time behavior is unraveled by theoretical between Ln3+ ions possible.However, the lack of adetailed modelling and confirmed spectroscopically.Based on this new microscopic picture of UC mechanism in such structures, fundamental insight, we have successfully realized fine control especially the ambiguous recognition of the energy migration of upconversion emission time behavior (either rise or decay dynamics and its effect on the time behavior of UC emission, process) by tuning the energy migration paths in various remains amajor bottleneck for further development of these specifically designed nanostructures.This result is significant structures. for applications of this type of materials in super resolution Based on traditional understanding,energy migration spectroscopy, high-density data storage,anti-counterfeiting, among sensitizers is always neglected in UC dynamics and biological imaging. treatment. In that case,although UC emission involves complex interactions between multiple Ln3+ ions,its dynamics Lanthanide (Ln) ions doped upconversion (UC) materials are solely determined by the energy transfer processes within have attracted extensive attention owing to their potential one activator–sensitizer pair (Figure 1a).[6] Despite some applications in alarge variety of fields,for example,display,[1] discussion of this assumption,[7] there is no direct evidence of the effect of the sensitizer-to-sensitizer energy migration on UC dynamics. [*] Dr.J.Zuo,[+] Dr.L.P.Tu,[+] Dr.B.Xue, Dr.Y.L.Zhang, Dr.Y.L.Chang, Prof. X. M. Liu, Prof. X. G. Kong, Prof. H. Zhang This unsatisfactory situation is primarily due to the lack of State Key Laboratory of Luminescenceand Applications, Changchun appropriate material systems.Indeed, even in the traditional Institute of Optics, Fine Mechanics and Physics, Chinese Academy of sensitizer–activator co-doping materials,energy migration Sciences still plays an important role in their UC process.[7a] However, Changchun 130033 (China) its effect is difficult to evaluate as the energy migration E-mail:[email protected] process is indistinguishable from energy transfer between [+] Dr.J.Zuo, sensitizers and activators.Inour opinion, this dilemma can be Universityofthe Chinese Academy of Sciences solved by introducing asmart nanosystem termed “dopant Beijing 100049 (China) ions spatial separation” (DISS) nanostructure.[5k] By locating Dr.J.Zuo[+] Dr.D.P.Sun,[+] Dr.Y.N.Wu, Prof. W. J. Buma, Prof. E. J. Meijer,Prof. H. Zhang sensitizers and activators into different regions of asingle Van’t Hoff Institute for Molecular Sciences, University of Amsterdam nanoparticle,the three basic processes of UC (i.e.light Science Park 904, 1098 XH Amsterdam(The Netherlands) absorption, energy migration, and UC emission) can be well E-mail:[email protected] separated (Figure 1b). Therefore,the role of energy migra- [email protected] tion in UC dynamics could be quantitatively determined by Dr.Y.H.Cao 1) tuning the migration layer thickness or 2) varying the College of Computer Science and Technology,Jilin University dopant concentration of the ions as energy carriers in the 2699 Qianjin Street, Changchun,Jilin 130021 (China) migration layer. Secondly,traditional treatment of the UC + [ ]These authors contributed equally to this work. mechanism based on simultaneous rate equations is not able Supportinginformation and the ORCID identification number(s) for to describe properly the actual energy migration processes, the author(s) of this article can be found under: because it provides only an averaged macroscopic statistical https://doi.org/10.1002/anie.201711606. result. Therefore,weset up atime-correlated Monte Carlo 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. simulation model to fill the gap (Figure S1–S7, Table S1–S3, KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, in the Supporting Information). Compared with previous [5e,7a,8] distribution and reproduction in any medium, provided the original approaches, our model is capable of monitoring UC work is properly cited, and is not used for commercial purposes. dynamics from the level of multiple ion-to-ion interactions, 3054 2018 The Authors. Published by Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim Angew.Chem. Int. Ed. 2018, 57,3054 –3058 Angewandte Communications Chemie delay should be mainly attributed to the additional Yb3+ Yb3+ energy migration time under the 800 nm ! excitation. Significance of this result is that:1)itisthe first acquisition in real time of energy migration contribution to UC emission, and 2) it confirms that the energy migration temporal effect is non-negligible. This result is consistent with the prediction of Monte Carlo simulation. In NaYF4 :20%Ybsublattice, despite each step of Yb3+ Yb3+ energy migration Figure 1. Schematic diagram of a) the traditional UC mechanism which relies on ! the monomer (sensitizer) to monomer (activator) sequential energy transfer only takes about 1.7 ms(Figure S5), and even if the interactions, and b) the UC process in the DISS nanostructure, in which the migration distance is just afew nanometers,the time three basic processes:photon absorption, energy migration, and UC emission delay for UC will still be several hundred micro- are spatially separated. seconds because 1) the random walk nature of energy migration, and 2) the non-linear nature of UC emis- yielding amore comprehensive vision without restric- tion of the distribution of Ln3+ ions in the nano- structure. Combining the experimental and simulation results,wefind that despite each step of the energy migration (e.g.Yb3+ Yb3+)only costs arelatively ! short time (around microseconds), its randomly walking nature significantly prolongs the migration time up to several hundred microseconds.This result tells us that the conventional understanding of the UC mechanisms is incomplete and in some nano- structures it might be misleading by ignoring the actual energy-migration process.More importantly, by precisely tuning energy migration paths in aDISS nanostructure,either the rise or decay of UC Figure 2. a) Schematic diagram of the experimental setup for binary pulsed emission dynamic traces can be quantitatively tail- (800 nm and 980 nm) excitation. b) The YbEr@Yb@YbNd UC nanostructure used in the binary pulsed excitation experiment. c) Time-gap (difference